This Means War
by soullessauthor
Summary: After the war with Valentine, Clary, Jace, Isabelle, and Simon get sent into the mundane world of high school. The four are forced to enroll in Clary and Simon's old school ,Goode High, where they meet a certain green eye boy. Although he seems friendly enough, Jace can't shake the feeling he gets around him. Who is this boy? and why does he seem so powerful?
1. Going Back to School

**Chapter One- Going Back to School**

Jace Lightwood P.O.V

"Come on Clary, just jump!" I called up to my girlfriend who was shuffling along the iron training bar.

Clary huffed irritably, "easy for you to say. You probably mastered this at the age of eleven!"

I grinned, "Actually I was eight!"

Clary rolled her eyes at my comment, "there's a time and a place, Jace. Besides, I'm not you; I'm going to break my neck or something."

This time I rolled my eyes at her. "Please, like I would let that happen. Just trust your blood."

My hard-headed girlfriend finally let out a sigh of acceptance and allowed herself to wrap around the flexible cord before she pushed off from the wall.

She flipped over and under, whirling and spinning with her natural angelic grace she so often ignored. She let out a little scream as she plunged through the empty space—but other than that she performed a beautiful shadowhunter flip.

She finished her flip by dangling upside down in front of me.

"Nice." I smirked, brushing some sweat stuck red hair from her face, "like a falling snowflake"

Clary gave a slight laugh, "doubtful. I screamed didn't I? On the way down?" she asked.

"Just a bit, but that will come with time." I told her.

She gave a slight tug on the rope that now restrained her, "do you mine getting me down? My bloods rushing to my head"

I gave her a devilish smile before swiftly removing a blade from my belt and cutting the cord.

Clary's eyes grew wide with surprise and fear as the speed of my movements caused her to fall freely through the air and into my outer stretched arms.

Once her body was safety coiled in my arms I gently tossed her on the mat, straddling my legs on either side of her hip.

"Now," I said while grinning down at her, "much better, you didn't even scream that time."

"I didn't really get the chance to," she said breathlessly, her emerald eyes still wide with shock.

I laughed softly and moved some wild red curls behind her ear, "It'll come with time and practice."

She gave a slight giggle, "I didn't even know you knew those words. I imagine you were naturally amazing at this stuff."

"I was born amazing," I said beaming down at her.

The feisty red-head playfully rolled her eyes, "and apparently, modest." She said sarcastically.

"Are you mocking me Fray?" I said faking hurt at her comment.

She shook her head, "Would I do something like that?" her voice dripping with fake innocence.

I was about to respond to her comment when the opening of the training room door interrupted me.

"Oh by the angel, why are you two _always_ in that position?" Isabelle's voice complained.

I rolled off of Clary and glared at my sister, "hello to you too Izzy. What do we owe this unwelcome surprised?"

Isabelle raised one of her perfectly plucked eyebrows-looking a lot like her mother Maryse when she wants me to "watch my tone."

"Sorry to interrupt your "training" but mom and Jocelyn would like to speak with us." Isabelle said in a bored tone, as she examined her nails.

"Why is my mother here?" Clary asked, coming up beside me.

The taller girl shrugged, "I don't know, I'm sure you'll find out when we talk to them."

Isabelle then turned on her heels and gracefully marched out of the training room, her black hair swaying behind her.

"I wonder what this could be about." Clary said softly while rubbing her elbow.

I shrugged, "probably nothing important. If it were, Alec would have been involved."

Clary sighed, "Come on, let's go see what they want. "

Clary Fray P.O.V

I walked next to Jace as we followed church the cat to the location of our mothers.

As we walked I couldn't help but wonder what would be so important that my mother would come back to the institute.

I knew she wasn't very thrilled with the idea of me dropping out of school in favor of training with the shadowhunters—but when she stole my memories she lost the right to dictate my choices in life.

Although, I still felt bad about my choice not to go back, seeing as how I was leaving Simon to deal with the chaos of high school without me.

I pushed that thought out of my head.

_Simon will be fine without me _I thought, _if not better. _

That thought—as true as it was—really stung my heart.

Simon's life really took a nose dive when I got wrapped up with Jace and the shadowhunters.

He got turned into a rat because of me, he became a vampire because of me, and now he was going to struggle with the horror of high school alone _because of me. _

Really great friend I am.

"You okay? You seem lost in thought." Jace asked me, as his luminous golden eyes searched my face.

I waved my hand at his comment and shot him a smile, "I'm fine. My mom and I are still butting heads, that's all"

Jace raised his eyebrows, "still about the whole school thing?"

I only nodded in response as church stopped and meowed at the closed kitchen door.

Jace thanked the fat cat and pushed open the wooden door.

When we entered Isabelle, her mother Maryse, and my mother sat around the table waiting for us.

"Sorry about the delay, we got a little "tied" up." Jace said sending me a wink.

Despite my efforts I blushed while Isabelle huffed in annoyance.

"No matter you're here now, sit" Maryse said, indicating her head to the two open chairs.

"Mom? What's this about?" I asked, sliding into the seat next to Jace.

My mother smiled knowingly at me, "nothing's wrong, Maryse and I just need to talk to you about something."

"Which is?" Isabelle asked slightly agitated.

Maryse sat up a little straighter in her chair and my mother shifted in her seat.

They both seemed very uncomfortable sitting next to each other.

"Jocelyn and I have talked about the training arrangements for Clary and have decided that it may not be the best idea." Maryse said calmly.

"What?! But you said I got to decide what path I followed" I gasped at my mother—out raged that she went behind my back.

My mother smiled sympathetically at me, "this wasn't my choice Clary. But without Hodge—"Jace, Isabelle, and Maryse visibly tensed "—there is no proper teacher for you to learn from. So, in till another teacher can be found you will go back to school"

Even though I was still angry at my mother I knew her reasoning made sense. There is no way she would allow Jace to continue to train me.

"Fine," I grumbled like a five year old, slumping back in my seat.

"Okay, that all sucks for Clary and everything, but why are we here." Isabelle said, indicating to her and Jace.

"Since you and Jace are not fully of age yet you two will also be going back to school." Maryse said to her children.

Both Isabelle and Jace looked shocked, "What?!" they both said.

"You can continue your training when I find a suitable teacher. But for now, you have to stay caught up in your studies." Their mother spoke forcefully.

Jace's jaw became set as he spoke, "you want me to go to high school to maintain my studies? I can speak five languages; I do not need some boring mundane school to teach me things I learnt when I was seven."

Maryse rolled her eyes at Jace, "stop being so dramatic Jace, It's only high school. You will go there for a few months while I search for a teacher. Who knows, you may even make some friends."

"I don't need any friends, I have Alec." Jace defended.

I really didn't know why Jace seemed so put off by the idea of school; he'd probably enjoy most of the school body bowing down to him.

"That doesn't count, he's your brother." Isabelle pointed out to him.

"Why are you on her side?" Jace questioned sending her a glare.

The black haired girl simply shrugged, "because unlike you I like meeting people and going to parties."

Jace opened his mouth to argue back at her but I cut him off,

"Jace relax, I'm sure you'll do just fine." I tried assuring him.

Jace looked over at me but didn't say anything.

Once Jace settled down Isabelle clapped her hands together.

"Oh, this is going to be so fun. You and I need to go shopping." She said looking at me.

I nodded and smiled faintly—joy, shopping with Isabelle.

Maryse and my mother rose from the table, "excellent, so it's settled. You'll start tomorrow."

"At what school?" Isabelle asked.

"Goode High." My mother answered looking over at me.

That was mine and Simon's old school before I got wrapped up in the shadow world.

"_Goode high?" _Jace repeated disapprovingly.

"Yes Jace, Goode High, Clary's old school." My mother said to him.

After that my mother and Maryse left the room leaving Jace, Isabelle, and myself sitting in an awkward silence.

"It's going to be so good to talk to new people." Isabelle cheered getting up from the table.

She walked over to the door and turned back to look at me, "come by my room later, I want to make sure your outfit looks hot for tomorrow."

I nodded as she walked out.

"Why are you so upset about going back to school?" I asked Jace.

He turned and grinned at me, "I'm not upset, I'm just worried.

I gave a fake gasp, "do my ears deceive me? Jace Lightwood is _worried?" _

Jace laughed a little and practically pulled me onto his lap.

"Yeah, who knows there could be someone better looking than me and they could steal you away."

I laughed loudly at this, "yes, that seems very likely to happen."

Jace smirked and pulled my head against his, "hey it could happen." He joked.

I pressed my lips to his, happy that he wasn't _really_ that upset about going to school.

"Okay I gotta go call Simon," I said getting off his lap.

Jace groaned loudly at this, "_he's_ going to be there?"

I nodded, "it's his high school too."

Jace sighed and thumped his head against his chair, "this just keeps getting better and better."

**Alright, so this story takes place after City of Glass and Blood of Olympus. Alec and Magnus are together, but not on vacation. "Sizzy" will only be in the later chapters, along with Percy/Annabeth. **


	2. Goode to Be Back

**Chapter two—Goode to Be Back **

**Percy Jackson P.O.V**

_I stood on top a platform overlooking blank emotionless faces. Iron tight chains wrapped around me, restraining my legs and arms in place. In front of me stood a tall white hair man who gripped a wooden podium as he passionately addressed the crowd of shadowy faces. _

_Panic started rising in my chest._

_Where am I? Who are these people? _

_I started to pull at the chains twisting my head back and forth looking for anything that I recognized. When I threw my head left I spotted another tall boy with golden hair and skin. His arms were wrapped around a small red hair girl. _

_Rachel? I thought. I tried to call out to her but no sound came. _

_Suddenly the crowd erupted into cheers as the white hair boy turned away from the podium. _

_He walked towards me carrying a silver cup that held black or dark red liquid. Something in the back of my head told me I wanted to stay away from that liquid. _

_I started pulling harder at the chains, but it was useless, I was trapped like a fly in a web. The man got closer and closer, each step becoming louder and louder in my head. _

_A pair of strong hands gripped the back of my hair, forcing my head back. I turned a little to find the golden boy, whose face I could barely make out grinning. _

_White hair boy stood right in front of me, smiling a cool triumphant smile, his eyes still masked by burliness. _

_He pressed the cup to my lips and the liquid rushed down my throat…._

"Beep! Beep! Beep!" my alarm clock cried next to me. I bolted up in a fright as my heart rate raced at the speed of a jack hammer.

_Just a dream_, I thought letting myself calm down, _only a demigod dream. _

I ran a shaky hand through my wild sweaty hair while taking some deep relaxing breaths.

"At least it wasn't Tartarus." I whispered quietly to myself, standing up to get dressed for the day.

I pulled on some fairly clean clothes, slung my backpack over my left shoulder and headed out of my room for breakfast.

Despite the fact that I was going to have to suffer through a horrid year of homework and most likely detention, I was actually looking forward to being a normal teenager again—well, as normal as a demigod can be.

I walked into the kitchen to find my mom sitting at the table typing on her lap top and drinking some coffee.

"Good morning," my mom said, smiling when I came in.

"Morning," I said while picking an apple up from the bowl of fruit in the middle of the table.

"How'd you sleep?" She asked me as I bit into the apple.

I shrugged and answered with a simple, "alright," while walking over to the fridge.

I routed around in the fridge until finally finding and pulling out the orange juice.

Sitting on the counter I pulled opened the carton and took a nice long drink from it.

"Percy," my mom said disapprovingly, "use a glass"

I gave a playful eye roll and smirked, "come on, no one else drinks orange juice."

She sighed and turned back to her computer, muttering something about teenagers.

"So, how's Annabeth?" she asked me as her fingers flew over the keys.

"She's fine. She's going to try to come up for thanksgiving." I said standing up to throw out my apple core and put the juice back.

"Well I hope she does," my mom turned her head to the kitchen clock and told me, "you'd better get going or you're going to be late."

I gave a loud groan, re-shouldered my back pack and grabbed my board.

"Alright, alright, I'm going. See you tonight." I told her, turning to open the door.

"Stay safe, try not to get killed and I love you!" she called as I walked through the door.

"I'll try! Love you too!" I yelled back, pushing off of my board and racing to the apartment exit.

For the first time in a while everything felt kinda normal.

**Clary Fray P.O.V**

"Excited for another joyful year at St. Xavier's?" Simon questioned me as we walked side-by-side to school.

I rolled my eyes at him, "God Simon, it hasn't been called that in five years."

He scoffed, "yes well, anything is better than 'Goode high'. I mean come on, how unoriginal is that?"

I had to admit he had a point, I was about to agree with him when my cell vibrated.

"Jace?" Simon asked as I reach into my pocket to pull out my phone.

"Most likely." I said while unlocking my cell.

_1 text message from Jace Lightwood 3 _

"Yeah, it's him." I smiled, tapping to read the message.

Simon gave a slight eye roll, "I _still _can't believe he's coming to school with us."

I hit him on the arm, "Hey, you said you'd try to get along with him."

"I am trying to get along with him. Maybe it's just natural for us to hate each other. You know the whole 'Shadowhunters vs. Downworlders' natural enemy's thing"

I laughed at that, "Well with that logic, mom and Luke can't get married, we can't be friends, Alec can't be dating Magnus, and you can't have your "on again off again, not really dating" thing with Isabelle."

"Whatever Fray." Simon pouted and started to text a message to someone in his phone—probably Eric.

I laughed again and turned my head to read the text.

_Where are you?! _

I gave a sigh and texted him back.

_Relax Jace. I'll be there in a few._

Simon and I walked in silence for a few more minutes until we reached Jace and Isabelle who were both wearing their normal black on black attire.

"What took so long?" Jace asked, coming up to link hands with me, "waiting for Simon to finish doing his hair?"

"Ha Ha Ha, so funny." Simon grumbled under his breath leading the way up the stairs to Goode High.

"I thought so," Jace responded smugly.

Simon opened his mouth to say something back but I cut him off.

"Okay, okay enough. Let's just go get our time tables."

All four of us made our way to the front office. When we got there we were greeted by an ancient grumpy looking woman who had her mousey grey hair pulled back in a tight bun.

"Names." She asked sharply, not looking up from her computer.

"Clary Fray," I answered quietly, the woman typed something into the computer before printing off a piece of paper.

"Here's your time table." She said bitterly, shoving the paper at me, "next."

Simon followed in after me, then Isabelle and last was Jace, who almost got himself a detention for a rather rude remark.

"Jace, can you tone it back a bit? It's not even the first hour." I said as we pulled a head of Isabelle and Simon

"What? I thought I was being charming, she probably _would _smile more if she got la—"

"Okay enough!" I stopped him.

He gave a small laugh and hooked his arm around my waist.

As we walked down the hallway most of the students turned to look at us, mostly because of Isabelle and Jace. However, for some reason Jace seemed unhappy by the reaction.

"Is it just me, or do they seem, I don't know, disappointed?" Jace asked as we continued to weave through the students.

"I pretty sure it's just you," I said as a group of cheerleaders flashed me death glares.

We made our way to a cluster of blue and black lockers.

One locker separated mine and Jace's, who was right next to Isabelle, as Simon claimed the one next to mine.

As I spun the combination of the lock I took a moment to pan the hallway, looking for two old friends.

"Rachel doesn't go here anymore." Simon said, watching me search the hallway.

My heart dropped a bit, I was looking forward to having art class with her again.

"What about—"I started to ask but Simons raised eyebrows and stupid grin stopped me.

"I knew you'd be looking for him! Wanting to see how he compares to Goldie locks over there?" he asked laughing as my face turned the same shade as my hair.

"Shut up!" I hissed, hitting him in the gut.

Simon—being the annoying vampire he was—didn't even blink at the hit and continued to laugh.

"Shut up about what?" asked Isabelle, who was leaning her ribbon thin body against the locker next to me.

"Clary's _little _high school crush," Simon said, laughing even more at Jace's slight tense reaction.

Isabelle gasped playfully, joining in on Simon's fun.

"Who is he?" She asked excitedly.

"Well he's—"Simon started to say but I cut him off.

"Don't you _dare" _I hissed at him, moving closer to Jace.

"Why so tense Fray? A little embarrassed"

I crossed my arms over my chest," no, I just think you need to drop it already."

Simon smiled widely, "consider this payback."

"Okay, does anyone feel like telling me what's going on?" Jace asked annoyed.

"Yeah come on, I wanna know" Isabelle agreed.

"Guys its nothing," I said.

"Come on! Tell me!" Isabelle begged.

"Alright, alright, it just had something to do with me and my friend Rachel." I said vaguely.

"He was a little more than _something" _Simon added.

I've never wanted to kill Simon more than at this moment.

I opened my mouth to snap back at Simon when a voice drew all our attention.

"Ah, sorry to break this up, but I need to get to my locker." The smooth melodic voice said.

_Damn_ I thought _so close. _

**Okay so the whole crush thing is just for fun, nothing will come about it. This is the first thing I've wrote something in a while—thanks to school. However, I have a really great idea for this story (thanks to CoHF) so I can't wait for this story to take off. Till next time :)**


	3. Baywatch

**Chapter Three—Baywatch **

Clary Fray P.O.V

"Ah, sorry to break this up, but I need to get to my locker." The melodic voice chimed from behind the group.

_Damn _I thought, _so close. _

"Speak of the devil," whispered Simon as all four of us turned to greet the new face, which happened to belong to Goode High's swim and surf team captain, Percy Jackson.

He stood in a casual relaxed stance, with his blue backpack slung on one shoulder, and his trident painted designed skateboard in his hands.

He had changed a bit since I last saw him, taller, more muscular, and yes—more attractive.

Percy stood a few inches taller than Jace, making him about 6 feet or more. Like Jace, Percy had lean muscles that twisted around his lanky dancer limbs, giving him a toned swimmers body. He had deeply sun kissed skin, making him look like he grew up on a sunny tropical island, and his hair fell in waves of ink black across his temple.

But the thing that made people really stop to look at Percy was his sea green eyes. They were so bright and warm; it was like soft waves hitting hot sand.

"Clary?" Percy questioned, his slight New York accent slipping into the name.

Jace shifted a little closer to me, his golden eyes staring hard into Percy's green ones.

I gave a slight wave, still a little embarrassed by what happened in the past and watched as Percy turned his attention to Simon.

"Simon? Geez, you guys sure changed," He said in a friendly tone, his face breaking out into a grin.

Another thing that Percy was famous for was his contagious grin, when he smiled it was practically impossible not to smile back—however, Jace was doing a pretty good job.

I couldn't help but notice that the whole hallway seemed to stop and watch Percy, almost like they were stunned to see him.

"Your one to talk," Simon smiled, as he embraced Percy in a bro hug.

Once their bodies met Percy seemed to flinch at Simons touched.

_Odd, _I thought.

After they broke contact they gave each other a light slap on the back and stood a healthy distance away.

"So, who are your friends?" Percy inquired, his eye flickering over to where Jace and Izzy stood.

"This is Isabelle Lightwood," Simon indicated with his hand.

Isabelle batted her eye lashes flirtatiously and extended out her hand to him.

"You can call me Izzy, and it's a pleasure to make your _acquaintance" _She said in her normal flirty tone.

"Um, thanks?" Percy said awkwardly—to Isabelle's disappointment—and kindly shook her hand quickly.

"And this is—"Simon started to say.

"Clary's boyfriend." Jace cut him off, his eyes seizing up Percy.

Percy eyes skipped over to Jace and a sudden flash of natural hate flickered in them.

"Man, finding key chains and mugs in souvenir shops must be rough." Percy said in a mocking sad tone.

I could see Simon suppress a laugh as Jace seemed a little put off by the statement.

"My names Jace," Jace said sharply.

Percy smirked a bit and turned to stand face to face with Jace.

"Got a last name Jace? Or are you going for the whole Cher thing? I mean you've got the cheekbones for it."

Simon busted out laughing, as Jace and Isabelle stared blank faced at Percy.

"Are you hitting on me? Because, no offence, but I prefer red heads."

I blushed slightly at that comment.

Percy only shrugged as his eyes seemed to flash more playful than before.

"That's okay, I prefer my blonds natural anyways."

Simon laughed even louder at that.

Jace opened his mouth to retort something back but Percy brushed past him to shove his bag and his skateboard into his locker.

"Nice to meet you all but I have to go see my step-father." Percy gave a salute wave and took off down the hall.

"I don't like him," Jace said as his gaze traveled after Percy.

"Is it because Clary had a crush on him? Or because he wasn't intimidated by you?" Simon asked.

"Wait _that's _the guy?" Isabelle asked shocked.

"That's the guy." Simon answered for me.

Jace hooked his arm back around my hips.

"Really Clary? I thought you could do better then some Baywatch wannabe."

I raised an eyebrow and grinned, "Baywatch? How do you even know what that is?"

"Magnus watches terrible TV," Jace said, looking like he was experiencing a war flash back.

"Well he's better than he seems," I said simply, turning to shut my locker.

"I don't know. Something about him seems off." Jace said warningly, leaning his cat like body against a closed locker.

"Why? Because he didn't tremble in fear of you?" Simon countered.

"No, well, not _just_ that, but something seems off about him. Isabelle you must have felt it."

Isabelle shrugged, "he's hot, and that's all I was paying attention to."

Jace huffed in annoyance, "come on, he's not a mundane."

All three of us turned to look at Jace.

"Well if he isn't a mundane, what is he?" Simon asked.

Jace shrugged, "I don't know, a Warlock with a hidden mark, a Werewolf, maybe even a Fairy, take your pick."

"Geez Jace, a mundane is more attractive than you so they must be a Downworlder." Isabelle laughed at her brother.

"He's not more attractive than me," Jace spat irritably.

"Sorry, but he is" argued Isabelle, sending a wink at a jock a few lockers down.

Simon scowled at this and closed his locker louder than he meant.

"Whatever don't believe me, but I'm positive that he's not a mundane and I'm going to prove it." With that Jace took out his cell and slammed some buttons.

He held up the phone to his ear and waited impatiently for an answer.

After a few more seconds Jace rolled his eyes before saying, "stop fucking your boyfriend and call me back."

"What, you're getting Alec involved now too?" Izzy questioned as Jace shut his cell.

"I need his opinion, and unlike you he doesn't get distracted by attractive guys," Jace paused and thought for a second, "I mean he does, but he's capable of ignoring it."

"Whatever we better get to class, see you at lunch." She said and strolled off.

"I better make sure she gets to the right class," Simon said and ran after her.

Once he was gone Jace turned and grinned at me.

"I'm better looking than him, right?" He said, curling me in his arms.

"Who? Simon? Because I think we already covered this topic." I said playfully.

Jace laughed, "Than Baywatch, your old crush."

I giggled and ruffled his hair, "first off it was before I met you, minster 'I've slept with half the girls in New York'" Jace winced at that, "it was a silly little crush, and yes, you are much better looking."

"Yes I know. I just like hearing you say that." He grinned and leaned down to kiss me.

Just before our lips met the bell rang to sound the start of class.

"Always some interruption," Jace smirked before he pressed his lips to mine.

"I gotta get to math," I said after his lips left mine, "I'll see you at lunch."

"You're seriously blowing me off for math," Jace whined as I moved out of his grip.

"Yes, and you should get going, Mr. Blofis doesn't like it when you're late."

**I'ma just stop myself there, next chapter will be Percy's P.O.V perhaps he thinks something's off about Jace. I am going to update my other stories this week "Who's the New Guy" and "Good to be back" included, I almost finished chapters for both. Sorry about not updating faster, I've just been soo busy and had such bad writers block. Also I've been thinking of another story idea that I really really really want to start. It's another PJO TMI crossover, however it won't have a MAIN plot line like this, it'll just be a story about an unlikely friendship between Percy and a well-known shadownhunter (try to guess who it'll be) Anyway, I hoped you like it, review :)**

**Also, there is a reason why Percy dislikes Jace. He did not, nor does he, have a crush on Clary **


	4. Back and Trasher Than Ever

_**Its been 84 yeeeeeeears!**_

*emerges like a frightened deer*

hi…so….it's been a while. I'm so sorry that I have not finished/ updated this story in a few years (holy its been years). Now, I have my reasons for not updating, one of them is that I've been mostly writing on my old tumblr blog (some of you have probably read some of my newer work on tumblr) and I sotra just forgot I had stories on this site. BUT I am no longer writing on tumblr and so I've decided to come back!

I missed you guys!

As for this story….I don't know what I'm going to do….I don't really remember what I was planning with this story….I might finish it… however I'm writing another mortal instruments/ percy Jackson crossover with one of my favorite new crack ships, so I might just add elements of this story into the new one.

Anyways I am back! I will be writing more fictions and I will be trying to finish and update my other stories.

I'm sorry that it has taken so long for me to get back into this site but I promise I will find a way to make it up to you guys.


End file.
